Control for multijet impulse turbine



March 28, 1961 s. R. NICHOLS CONTROL FOR MULTIJET IMPULSE TURBINE 2 Sheets-Sheet 1 Filed July 16, 1956 swam kart M @MM CONTROL non MULTIJET IMPULSE TURBINE Beverly R. Nichols, Elm Grove, Wis, assignor to Allis- Chalmers Manufacturing mpany, Milwaukee,- Wis.

Filed July 16, 1956, Ser. No. 598,121

11 Claims. (Cl. 60-97) This invention relates to a hydraulic turbine of the impulse type which has a plurality of nozzles directing jets of water at buckets carried on the runner of the turbine, and more particularly to an arrangement for controlling the turbine.

Originally, a single nozzle was provided to rotate the runner of an impulse turbine. Where greater motive power was required, another runner was usually provided on the same shaft, and another nozzle added to rotate the second runner. Greater space, as well as the two runners that were required, rendered this arrangement costly. The present day solution to this arrangement is to provide a plurality of nozzles and a single runner. However, when using a plurality of nozzles, it is diflicult to provide a flexible control system which will permit the turbine to run at best efficiency under varying conditions. For example, for best efliciency when starting the turbine, it is more eflicient to use one or two nozzles fully opened than six nozzles partially opened due to the friction losses in six partially opened nozzles. Additionally, the system should be capable of varying the speed of the turbine runner under different conditions.

An object of this invention is to provide a control system for limiting the amount the nozzles may be opened, by limiting the range of movement of the needles which move in the nozzles.

Another object of this invention is to provide a control system permitting quick determination of the position of each needle in each nozzle.

A further object of this invention is to provide an interlock system operative during closing of all the nozzles, to operate switches to actuate electrical control circuits.

A further object of this invention is to provide an arrangement to indicate the largest nozzle opening of the plurality of nozzles.

Other objects and advantages will appear from the following description considered in conjunction with the attached drawings, in which:

Fig. 1 is a plan view of the turbine, with certain parts in section, showing the nozzles, deflectors and the runner;

Fig. 2 is a schematic showing of the system for controlling the operation of the runner;

Fig. 3 is an enlarged portion of the system disclosed in Fig. 2 showing the relative relationship of the sprockets, bevel gears and collars, on the main shaft; and

Fig. 4 is an enlarged cross section of a portion of Fig. 2 showing the interior of a mercury switch supported on a shaft.

Referring to Fig. 1 there is disclosed an impulse type turbine having buckets 2 in its periphery upon which jets of water impinge to rotate runner 4-, which drives shaft 6 to rotate a generator (not shown). Fluid enter through a penstock 8 and exits through a plurality of nozzles 10 (six being shown), which areprovided to control and direct jets of fluid against runner 4.

Each nozzle 10 (referring to Figs. 1 and 2) has a movable needle 12 which controls the size of opening 14 in the nozzle and a deflector 16 (Fig. 1) positioned $76,687 Patented Mar. 28, 1961 adjacent each nozzle 10. Each deflector is pivotally movable into and out of a jet to rapidly deflect a portion of the jet, in response to changes in speed of the turbine runner, to control the amount of fluid directed against runner 4. If the openings in the nozzles were quickly closed by the needles in response to changes in speed of the turbine runner, a shock wave resulting from the kinetic energy of the fluid would result, having a destructive effect on the conduits admitting fluid to the turbine. The purpose of each deflector 16 is to deflect a portion or all of the jet from runner 4 to provide immediate control over the speed of the runner, while permitting needles 12 to close more slowlyin response to changes in speed of the turbine runner to prevent the shock wave from forming.

Speed responsive means (indicated generally by arrows 17, Fig. 2) are provided to interpret and modify increases or decreases in the speed of the turbine runner to provide movement which can be utilized to control the needles. The speed responsive means however, are not powerful enough to move the plurality of needles. Individual secondary power devices (indicated generally by numeral 18) are provided to move each of the needles, andindividual connecting means (indicated generally by numeral 19) are provided to connect an individual secondary power device and the speed responsive means so as to operate each of the secondary power devices in response to movement of the speed responsive means.

The speed responsive means may comprise a governor arrangement (indicated generally by numeral 21) movable in response to increases or decreases in speed of the turbine runner to move the deflectors, and a control means (indicated generally by numeral 23) to modify the movement caused by the governor arrangement to give the needles the correct amount of movement for best efliciency. I

The governor arrangement comprises: a motor 2t) which is electrically connected by wires 22 to a permanent magnet generator (not shown) directly connected to the shaft of the turbine, so that the speed of the motor will vary as the speed of the turbine runner. The motor rotates a flyball governor 24 which is connected to movable piston 26 of main valve 28 to move the piston from a neutral position to control a servomotor 30.

Movable piston 26 controls flow of fluid under pressure.

from inlet pipe 27 through main valve 28, in response to increases or decreases in speed of turbine runner 4, to move piston 32 and piston rod 34 in a desired direction. Any conventional device (not shown) may be provided to return piston 26 to its neutral position as is well known in the governor art.

Since deflectors are adjacent the jets, means must be provided to connect the deflectors with the governor arrangement. Referring to Fig. 2 piston rod 34 of main servomotor 30 is pivotally connected to link 38 which is fixed to deflector shaft 40 rotatably supported in bearings 41. Deflector drive shaft 40 carries a double arm 42 at its end. Pivotally connected to each end of the double arm is a control link 44 (Fig. 1). Each control link 44 is connected to one end 45 of a bell crank 46 which pivots about its center 48. Fixed to the center portion of each bell crank 46 is a deflector 16. End 50 of each bell crank is connected to a link 52 which is pivotally connected to end 53 of a second bell crank 54 which also carries a deflector 16 fixed to its center. End 56 of hell crank 54 is pivotally connected to a third link 58 pivotally con nected to a lever 60 also having a deflector 16 fixed to its end. This provides an arrangement whereby the six deflectors are rotated by a single deflector drive shaft 40. The governor arrangement 21 rotates deflector drive shaft 40 which in turn causes deflectors 16 to pivot into and out of their associated jets.

1110 (one for each nozzle).

Control means 23 which modifies the movement caused by the governor arrangement 21 and which moves connecting means 19 to operate the individual secondary power 'devices 18, may comprise: a power device 78 operated by and connected to the governor arrangement, a control cam 34 rotated by said power device, a cam shaft 86 rotated by said control cam, and a plurality of control arms 1% rotated by said cam shaft. Referring to Fig. 2, link 38 rotated by piston rod 34 of the governor arrangement, is pivotally connected to a drive link 66 in turn pivotally connected to one end of a bell crank 68, which rotates about a pivot 70. The other end of the bell crank ispivotally connected at 71 to the intermediate portion of floating link 72. The floating link operates a power. device (indicated generally by numeral 73) which may comprise a control valve 78, and a control servomotor 811 operated by said control valve. End 74 of the floating link is pivotally connected to piston 76 of control valve 78; raising or lowering of piston 76 regulates flow of fluid under pressure from inlet pipe 77 operating control servomotor 80. Piston rod 82 of control servomotor 80 is pivotally connected to a control cam 84 which rotates control shaft Sdrotatably supported by bearings 88.

Fixed to the control shaft are a plurality of control arms Each individual control arm moves an individual connecting means 19 which operates an individual secondary power device 18. The intermediate portion of floating link '72 carries a rotatably mounted cam follower '93 which rests on surface 92 of said cam 84. End 94 of floating link 72 is connected to spring 9 8 which is connected to the frame to urge the cam follower against the cam.

Assuming piston 76 is in its off position and has disconnected the control servomotor from the source of fluid; the control means operate in response to movement of the governor arrangement in the following manner: drive link 66 when moved by link 38, will cause bell crank 68 to rotate about pivot 70 to force floating link 72 to pivot about follower roller 90 to either raise or lower piston 76 from its'oif position. Control valve 78 will then admit fluid to either side of control servomotor 80 to cause control cam 84 to rotate control shaft 86 and the plurality of control arms 100. When control cam 84 is rotated by control servomotor 80, cam follower 90 will be moved by cam 84 to cause floating link 72 to now pivot about pivotal connection 71, in a direction opposite to the direction that the floating link was pivoted to actuate the valve. This will move piston 76 back to its off position and stop the flow of fluid to control servomotor 80.

The individual secondary power devices which are provided to move each needle may comprise a needle servomotor 102 (Fig. 2), and a secondary valve 104, having a piston 163 to control fluid under pressure from inlet pipe 1119 through tubing 111 to the needle servornotor. Each individual secondary valve is operated by oneof the individual connecting means which is moved by one of the control arms 1% rotated by control shaft 86.

Each individual connecting means 19 which connects each secondary power device to each control arm 100, is the same, therefore only one connecting means will be described. The connecting means may comprise a second floating link connection (106, 136, 13-4, 132, 137, 133) to operate secondary valve 134 to control flow of fluid to the needle servomotor 102, and yieldable means 114 joining the second floating link connection and the control arm 100.

The second floating link connection comprises a second floating link 1116, and a sheave 136 to move the second floating link in a direction opposite to the direction that control arm 1% moved the second floating link. Connected to piston 103 of secondary valve 104 is one end of second floating link 1156. Yieldable means 114 is pivotally connected. at 112 to the other end of said second floating link 1% and pivotally connected at 116 to control other nozzles.

arm 1%. Intermediate the length of second floating link 106, a pivotally mounted foot 132 is carried. Foot 132 is slidably mounted in a support 133 The foot is urged by a spring 137 against a projection 134 carried on a sheave 136 (or spring 137 may be dispensed with and the foot made heavy to maintain the foot against the projection so that the floating link will rotate about, rather than lift, the foot). The sheave is fixed to shaft 138. Sheave 136 and shaft 138 are carried by a fixed bar 139 supported at 140. Inasmuch as there are six nozzles, bar 139 will support six shafts and six sheaves (not shown). The sheave is attached to a cable 142 which passes over pulleys 144 and is joined at 145 to a projection 146 (Fig. 2) extending from needle 12. The other end of the sheave is connected to a weight 152 to take up slack in cable 142. When a needle is moved, the sheave and shaft 138 will be rotated relative to bar 139 either by cable 142 or weight 152, to move the second floating link 106 in a direction opposite to the direction it was originally moved by control arm 1011.

Assuming valve piston 1&8 is in its off position and has disconnected the needle servomotor from its supply of fluid, the needle power devices and means connecting the needle power devices to the speed responsive means operate in the following manner: in response to movement of control arm 100 of the speed responsive means, second floating link 1% is moved upwardly or downwardly by yieldable means 114. The floating link, when it rotates about foot 132, will raise or lower piston 1% from its off position to regulate fluid flow to needle servomotor 102 and move needle 12. Needle 12 will move projection, 146, and cause cable 142 orweight 152, to rotate sheave 136. Sheave 136 will, on rotating, raise or lower foot 132 which rests on projection 134. The raising or lowering of the foot will cause the second floating'link to pivot about pivotal connection 112 and move piston 1118 of the secondary valve 164 in a direction opposite to the direction that piston 108 was originally moved. This will move piston 1118 of secondary valve 104 back to its off position and stop the flow of fluid to the needle servomotor to stop movement of the needle.

Control of needle orifice size Yieldable means 114 is utilized to permit the size of the orifice 14 in the nozzle to be limited and still permit the speed responsive means to control the orifice size in The yieldable means comprises a spring urged, two part rod, which is divided into two telescoping parts 153, 155. One part 155 carries tubular portion 157, and the other part 153 carries an enlarged head 159 which is received within tubular portion 157. Carried within tubular portion 157. is a spring 161 to urge head 159 against bottom 163 of t the tubular por tion; yet permit said head to move away from bottom 163.

to form a yieldable connection. The open end of the tubular portion is partially closed at 165 to prevent the spring and head from moving out of the tubular portion while still permitting passage of rod 153. Spring 161 will not be compressed under ordinary circumstances when transmitting motion from control mm 100 to second floating link 1136. A stop 167 is carried on rod part 155 for engagement with a limit means 154 carried on support 150. Limit means 154 is adjustable and movable into the path of stop 167 carried by rod part 155, to prevent [floating link 106 being moved by the speed responsive means 17 to operate a needle servomotor to move a needle and open a nozzle farther.

The limit means 154 is affixed to the frame and is rotatably mounted at its center by pivot 156. Adjustment means (158, 161 177) are provided to rotate the limit means 154 about pivot 15 6 to move the limit means into the path of a stop; to vary the position of the limit means and modify the range of movement of stop 167; and if desired, close a nozzle by moving the stop in reverse direction. The position of the limit means may be manually varied by the adjustment means, or automatically varied by a conventional solenoid, motor, or hydraulic cylinder. In the embodiment disclosed, each of the limit means is provided with an adjustment means which is manually operable to vary the position of the limit means, and which may comprise: a threaded shaft 158 rotatably supported by the frame, and a nut 16!), which is pivotally and slidably mounted in one end of the limit means, to receive threaded shaft 158. The threaded shaft is rotated by knob 177 rotatably supported by support 150 (Figs. 1 and 2) and causes the nut to move along the shaft and the limit means to rotate about pivot 156. When arm 1% moves counterclockwise (as viewed in Fig. 2) stop 167 will engage limit means 154. The limit means will prevent floating link 1106 from being moved by the control a'rrnto further open the nozzle. However, when control arm 1% moves clockwise (as viewed in Fig. 2), head 159 can move against bottom 163 of tubular portion 157 to move the second floating link and close the nozzle. When the range of movement of a needle has been limited by the limit means, an arm 101) of the speed responsive means attempts to move the yieldable means 114 to operate a power device 102 to open a nozzle further, spring 161 carried in tubular portion 157 of rod part 155 will be compressed (as shown in Fig. 2) between head 159 and partially closed end 165 of tubular member 157 and permit rod part 153 to move relative to rod part 155. This stretching of the yieldable means allows control shaft 86 to move when the range of movement of a connecting means is limited, so it can control other nozzles. This arrangement also allows control shaft 86 to close all of the nozzles in response to the speed responsive means. Further, when it is desired to close some of the nozzles, for example when starting the turbine, all that is required is that a knob 177 be rotated forcing its limit means 154 to move stop 167 to actuate needle servomotor 162 so that it will move its needle to close the nozzle, or if the nozzle is closed, prevent the nozzle from being opened.

Individual needle position indicator The position of each individual needle is visually indicated by individual position means. Inasmuch as the individual position means are the same, only one has been illustrated. Each individual position means comprises: means (138, 162, 164, and 174) moved by a needle to rotate a rotatable member (166, 169), and an indicator means (171, 172, 173 and 175) rotated by the rotatable member.

The means moved by a needle to rotate the rotatable member 166, 169 comprises a disk 162 connected to shaft 138 rotated by sheave 136, a chain 164, and a weight 174. One end of chain 164 is fixed to said disk, and the other end of the chain extends from the disk to the rotatable member. Rotatable member (166, 169) comprises a driven element such as sprocket 166, and a bevel gear 169 fixed to said sprocket. The rotatable member is carried on a main shaft 168 which is rotatably supported in bearings 176). The rotatable member rotates relative to main shaft 168. Weight 174 is carried on the end of chain 164 so sprocket 166 will be rotated when disk 162 plays out the chain. There will be six spaced rotatable members carried on the main shaft inasmuch as there are six nozzles.

Each rotatable member rotates an indicator means, comprising a pinion 171 rotating a pinion shaft 172 carrying a pointer 17?: at its end. Pointer 173 cooperates with index marks 175 on support 156 (Figs. 1 and 2) to indicate the positionof the needle. Pinion 171 is rotated by bevel gear 169.

Each of the position means operates in the following manner: when sheave 136 is rotated by movement of a needle, the sheave will in turn rotate shaft 138, disk 162, chain 164, sprocket 166 and bevel gear 169 which is connected to the sprocket. The bevel gear will rotate pinion 171, pinion shaft 172 and pointer 173, to indicate the position of the needle. There is, as stated above, a separate rotatable member 166, 169, pinion 171 and pointer 173 provided for each needle.

Control circuit interlock An interlock means (168, 176, 178, 180, 182, 184, 186, 188 and 189) is provided to operate switches 190 by either opening or closing the switches to actuate electrical control circuits during the closing of all the nozzles. Actuate is defined as energizing or deenergizing the control circuits. The control circuits may be employed to control any desired characteristics of the turbine, for example: actuate brakes to stop the turbine, open circuit breakers, interlock the power house with switchgear, trip the main breaker when the load is down to no load speed, etc. The interlock means is designed so that it will be operated only by the closing movement of the last needle, or needles, of the group to close, regardless of which of the needles it is of the group which is last to close.

The switches are operated by movement of the main shaft 168 through a predetermined arc in response to closing of the nozzles. Means are provided for rotating the main shaft 168 clockwise (as viewed in Fig. 2), and may comprise a disk 182 fixed to the main shaft, carrying a weight'184 to rotate the disk and main shaft 168. Carried on the main shaft is a collar 178 for each needle. Each collar 178 is fixed to main shaft 168 and carries an abutment 18f) (Figs. 2 and 3) to engage a finger 176 provided on each sprocket 166.

There will be six abutments since there are six nozzles. The abutments extend from the collars in a common plane parallel to the main shaft (Fig. 3). The fingers will extend from their sprockets in a common plane parallel to the main shaft only when all the needles are in the same position, for example, when all the nozzles are closed. The main shaft will be rotated clockwise by weight 184 until an abutment on a collar 178 abuts a finger 176 011 a sprocket 166 and the finger prevents further clockwise rotation. The position of each finger 176 will depend on the position of its needle. Assuming that all the nozzles are open, when a needle is moved to close a nozzle, the needle will pull on cord 142 rotating sheave 136 clockwise (Fig. 2) to rotate shaft 138, disk 162, chain 164, sprocket 166 and finally, finger 176 clockwise to a new position. However, merely moving one finger away from one abutment will not permit the main shaft to rotate. There are six fingers; the remaining five fingers must also be moved before the main shaft can rotate clockwise. As long as one finger has not moved, or moves less than the other fingers (i.e., its needle moves the least of all the needles and therefore its nozzle remains open wider than any of the other nozzles) that finger will engage an abutment on a collar and prevent the main shaft from moving, even though the other five nozzles may be closed and their fingers moved out of the path of movement of the remaining abutments. Therefore, as long as one nozzle remains open, the main shaft will be prevented from moving through its predetermined arc and the switches will not be operated. Obviously, when a nozzle or nozzles are being opened, the needles will move their fingers to rotate against the abutments and move the main shaft in the opposite direction (counterclockwise in Fig. 2).

The plurality of switches are actuated by said main shaft when it is allowed to rotate through a predetermined are in response to the closing movements of all of the nozzles. Any conventional means may be provided to actuate the plurality of switches in response to movement of the main shaft through said predetermined are. In the embodiment disclosed, the main shaft carries bevel gear 186 at its end which rotates a pinion 188 and pinion shaft 189. Pinion shaft 189 carries a plurality of switches 1% around its periphery which are illustrated as mercury switches. Referring to Fig. 4, a mercury switch 190 is disclosed which has not been actuated. When shaft 189 rotates counterclockwise, mercury 191 will flow and engage contact 192 to complete an electrical connection. Mercury switches 190 may be used to control any desired characteristics of the turbine as stated above.

Largest nozzle opening indicator Since there are a plurality of nozzles, it is necessary to observe and compare the position of each needle as indicated by each needle position means. Means 14 2, 136, 138, 162, 164, 166, 176, 178, 180, 186, 183, 189, 200, 202operated by said needles are provided to determine the size of the largest nozzle opening. Inasmuch as the main shaft is prevented from moving by the finger moved by the needle forming the largest nozzle opening, the position of the main shaft may be employed to quickly indicate the size of the largest nozzle opening. Means are operated by the main shaft to translate the angle of rotation of the main shaft into the size of the largest nozzle opening. The end of pinion shaft 189, which is rotated by the main shaft, is provided with a contact 200 which engages a potentiometer 202. As the main shaft rotates contact 2% will slide along the potentiometer and indicate a different voltage for each position of the main shaft. Any conventional electrical indicator may be connected to potentiometer 202 and calibrated to indicate the size of the largest nozzle opening. For example, a voltmeter (not shown), may be calibrated to read directly in percent nozzle opening rather than voltage.

Rsum

In summary, the turbine controlling system operates in the following manner: the speed responsive means 17 comprises a governor arrangement 21 and a control means 23. The governor arrangement includes a servomotor 31? to rotate deflector drive shaft 40 to move deflectors 16 in response to changes in speed of the turbine runner. The governor arrangement also operates control means 23 which includes control servomotor 80 to rotate control cam 34, and control shaft 86 which carries an arm 100 for each nozzle. The control means modifies the movement caused by the governor arrangement to move the needles the correct amount in response to changes in speed of the turbine runner. Inasmuch as the speed responsive means is not powerful enough to move the needles, individual needle servomotors 102 are provided to move each needle. Control shaft 86 rotates control arms 1% to control individual secondary valves ..which in turn control the individual needle servomotors 10 2 which move the needles.

Each control arm 160 is connected to an individual secondary valve through a two part rod which has two telescoping parts 153, 155 and a spring connection 161. Rod part 155 carries a stop 167. A needle whose range of movement is to be limited is selected. Limit means 154 is provided to engage stop 167 to limit movement of rod part 155 and as such, the range of movement of the selected needle. The spring connection, however, yields under compression caused by a control arm attempting to move the needle to open a nozzle and permits rod part 153 which is connected to control arm 100 to move, so that control shaft 86 can rotate and control unselected needles which have not been prevented from moving.

Each needle on moving, rotates a sheave 136 to rotate a shaft 133, disk 162, chain 164, a sprocket 166 loosely carried on main shaft 168, a bevel gear 169 which is connected to the sprocket, a pinion 171 and a pointer 173 to indicate the position of each needle.

The control circuits are actuated in response to rotation of the main shaft. The main shaft, when permitted, is rotated by weight 184. A collar 178 (Fig. 3) fixed to the main shaft, is provided for each sprocket 166. Each sprocket carries a finger 176 to engage an abutment 180 on a collar to prevent main shaft 168 from rotating. The finger 176 on'a sprocket which has been rotated least (i.e. the finger of the nozzle which has an opening larger than the other nozzles), will engage an abutment 18 on a collar and prevent the main shaft from rotating. Carried on the end of the main shaft is bevel gear 186 (Fig. 2) which rotates pinion 188, to rotate pinion shaft which carries mercury switches at various angles on its periphery. The mercury switches are actuated as pinion shaft 189 is rotated through a predetermined are by the main shaft.

Carried at the end of pinion shaft 189 is contact 209 which engages potentiometer 202 to indicate the largest nozzle opening of the plurality of nozzles as indicated by the rotation of the main shaft.

This control system provides a single, simple arrangement to control a plurality of needles; an arrangement for closing any desired nozzle, by or for blocking any needle so that it will not open a nozzle beyond a predetermined point, Without affecting the operation of any of the other needles; an interlock to actuate control circuits with the closing movement of the needles, irrespective of which of the needles are last to close, and finally, an arrangement for quickly determining the largest nozzle opening of a plurality of nozzles, as well as the position of each individual needle.

Although but a single embodiment of the present invention has been illustrated and described, it will be apparent to one skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

What is claimed is:

1. A control system comprising; speed responsive means, individual power devices, individual means connecting each power device and the speed responsive means, said speed responsive means moving said individual connecting means through a range of movement to operate each of said individual power devices, each of said individual connecting means including yieldable means, individually movable limit means operatively connected with individual connecting means, said individual limit means movable into the path of individual connecting means to decrease the range of movement of said connecting means, and individual adjustment means connected to individual limit means for moving individual limit means into the path of individual connecting means, a selected adjustment means moving a selected limit means to limit the range of movement of a selected connecting means and in turn limit the range of movement of a selected power device, said speed responsive means stretching said yieldable means of said individual connecting means which have been prevented from moving by a selected one of said individually movable limit means, so that the speed responsive means can move to operate all of said power devices except those power devices that are connected to connecting means which have been prevented from moving by a selected one of said individually movable limit means.

2. A control system comprising; speed responsive means, a power device, means connecting said power device and said speed responsive means, said speed responsive means moving said connecting means through a range of movement to operate said power device, limit means operatively connected with said connecting means, said limit means movable to engage and limit the range of movement of said connecting means and in turn limit the range of movement of said power device, adjustment means connected to said limit means to move said limit means, a main shaft carried by a support, a rotatable member carried by said main shaft, means interconnecting said power device and said rotatable member, said interconnecting means rotating said rotatable member relative to said main shaft in response to movement of said power device, and indicator means connected to said 9 rotatable member to be rotated by said rotatable member to indicate the position of said power device.

3. A control system comprising; speed responsive means, individual power devices movable through a range of movement between a first position and a second position, individual means connecting each power device and said speed responsive means, said speed responsive means moving said individual connecting means through a range of movement to position each of said individual power devicm, said power device having said first position corresponding to the position of said individual connecting means when said speed responsive means responding to high speeds initiates movement of said individual connecting means and said power device having said second position corresponding to the position of said individual connecting means when said speed responsive means responding to high speeds completes movement of said individual connecting means, individually movable limit means operatively connected with individual connecting means, said individually movable limit means movable to engage and limit the range of movement of selected individual connecting means and in turn limit the range of movement of selected power devices, individual adjustment means connected to individual limit means to move said individual limit means, interlock means connected to said power device to be operated by said power device moving to said second position, a plurality of switches mounted on said interlock means, said interlock means operating said switches to actuate electrical control circuits.

4. A control system comprising; speed responsive means, individual power devices movable through a range of movement between a first position and a second position, individual means connecting each power device and said speed responsive means, said speed responsive means moving said individual connecting means through a range of movement to position each of said individual power de vices, said individual power devices having said first position corresponding to the position of said individual connecting means when said speed responsive means responding to high speeds initiates movement of said individual connecting means and said individual power devices having said second position corresponding to the po sition of said individual connecting means when said speed responsive means responding to high speed completes movement of said individual connecting means, individually movable limit means operatively connected with individual connecting means, individual adjustment means connected to individual limit means for moving individual limit means, individual limit means movable to engage and limit the range of movement of individual connecting means and in turn limit the range of movement of individual power devices, and means connected to said power device to be operated by said power device to indicate the position of the power device that has moved closest to said first position.

5. A control system comprising; speed responsive means, individual power devices movable through a range of movement between a first and second position, individual means connecting each power device and the speed responsive means, said speed responsive means moving said individual connecting means through a range of movement to position each of said individual power devices, said individual power devices having said first position corresponding to the position of said indivdual connecting means when said speed responsive means responding to high speeds initiates movement of said individual connecting means and said individual power devices having said second position corresponding to the position of said individual connecting means when said speed responsive means responding to high speeds completes movement of said individual connecting means, individually movable limit means operatively connected with individual connecting means, individual adjustment means connected to individual limit means for moving said individual limit means, said individual limit means movable to engage and limit the range of movement of individual connecting means and in turn limit the range of movement of selected power devices, position indicating means for each power device, means connecting an individual position indicating means and an individual power device, each individual position indicating means moved by the power device to which it is connected to indicate the position of that power device, interlock means connected to portions of said individual position indicating means which are connected to said power device to be operated by said power device, a plurality of switches mounted on said interlock means, said interlocking means operating said switches to actuate electrical control circuits, and means connected to portions of said interlock means which are connected to said power device to be operated by said power device to indicate the position of the power device that has moved closest to said first position.

6. A control system comprising; speed responsive means, individual power devices, individual means connecting each power device and the speed responsive means, said speed responsive means moving said individual connecting means through a range of movement to operate each of said power devices, each of said connecting means including an individual stop, and individual movable limit means mounted in spaced relation to each of said connecting means and movable into the path of movement of each stop to operatively engage each stop, individual adjustment means connected to each limit means to vary the position of selected limit means with respect to selected stops, each of said adjustment means comprising a threaded shaft rotatably carried by a support, a nut pivotally and slidably carried by said limit means, said threaded shaft threadedly received by said nut, means connected to said shaft to rotate said shaft to move said nut and move said limit means, selected limit means limiting the range of movement of selected stops and in turn limiting the range of movement of selected power devices.

7. A control system comprising; a governor arrangeent, a control valve connected to said governor arrangement to be actuated by said governor arrangement, a control servomotor connected to said control value to be operated by pressurized fluid controlled by said control valve, a cam connected to said control servomotor to be rotated by said control servomotor, a control shaft connected to said cam to be rotated by said cam, a plurality of control arms fixed to said control shaft, means connected to said cam to be moved by said cam to deactuate said control valve, an individual power device for each control arm, individual means connecting an individual power device and a control arm, each of said control arms moving each of said individual connecting means through a range of movement to operate each of said individual power devices, each of said individual connecting means including an individual yieldable means, individually movable limit means engageable with individual connecting means, individual adjustment means connected to individual limit means for moving said individual limit means and thereby provide for moving a selected limit means to engage a connecting means to limit the range of movement of said connecting means and in turn limit the range of movement of a selected power device, said control arm stretching said individual yieldable means of said connecting means which have been prevented from moving by said limit means when rotational movement of said control shaft exceeds that required to engage the selected individual limit means with a connecting means.

8. A control system comprising; speed responsive means, a plurality of secondary valves, an individual servomotor connected to an individual secondary valve to be controlled by said individual secondary valve, an individual link connected to each of said individual secondary valves to actuate each of said individual secondary valves, individual means interconnecting each of said individual servomotors and each of said secondary valves to be moved by each of said individual servomotors to 1 1 deactuate each of said secondary valves, individual yieldable means connecting each of said links with said speed responsive means, said speed responsive means moving said links through a range of movement to operate each of said secondary valves, individually movable limit means engageable with individual connecting means,

individual adjustment means connected to individual limit means for moving individual limit means to engage a selected yieldable means to limit the range of movement of selected links and in turn limit the range of movement of selected servomotors, said speed responsive means stretching said selected yieldable means which has been prevented from moving by said limit means when movement of said speed responsive means exceeds that required to move said selected links to the position where said selected limit means engages selected yieldable means.

9. A control system comprising; individual power devices, a speed responsive arrangement, said speed responsive arrangement connected to each power device to operate each power device, a main shaft carried by a support, a rotatable member for each power device carried by said main shaft, said rotatable members rotatable relative to said main shaft, an individual means connecting a power device and a rotatable member, each individual means moved by a power device to move a rotatable member in response to movement of its power device, and an individual indicator means connected to each rotatable member to be moved by each rotatable member to indicate the position of each of said individual power devices.

10. A control system comprising; individual power devices movable through a range of movement between a first and second position, a speed responsive arrangement, individual means connecting each individual power device and said speed responsive arrangement, said individual connecting means movable through a range of movement in response to said speed responsive arrangement to position said individual power devices, said individual power devices having said first position corresponding to the position of said individual connecting means when said speed responsive arrangement responding to high speeds initiates movement of said individual connecting means and said power device having said second position corresponding to the position of said individual connecting means when said speed responsive arrangement responding to high speeds completes movement of said individual connecting means, a main shaft carried by a support, a driven element for each power device carried by said main shaft, said driven elements rotatable relative to said main shaft, individual means connecting a power device and a driven element, said individual means moved by each power device to rotate each driven element, a collar for each driven element fixed to said main shaft, an individual abutment carried by each collar, an individual finger carried by each driven element extending into the path of movement of each abutment, means connected to said main shaft to rotate said main shaft to move an abutment into engagement with a finger, each of said individual means rotating its driven element and finger in an arc in response to movement of its power device, a plurality of switches connected to said main shaft, means operated by said main shaft to operate said switches when said main shaft rotates through a predetermined arc, each finger of each power device which is in said first position extending into the path of rotation of said abutments to prevent 'said main shaft from rotating through said predetermined are, said power devices when moving to said second position moving said fingers so thatsaid main shaft rotates through said predetermined arc to actuate said control circuits.

11. A control system comprising; individual power devices movalble through a range of movement between a first and second position, a speed responsive arrangement, individual means connecting each individual power device and said speed responsive arrangement, said individual connecting means movable through a range of movement in response to said speed responsive arrangement to position said individual power devices, said individual power devices having saidfirst position corresponding to the position ofs-aid individual connecting means when said speed responsive arrangement responding to high speeds initiates movement of said individual connecting means and said power device having said second position corresponding to the position of said individual connecting means when said speed responsive arrangement responding to high speeds completes movement of said individual connecting means, a main shaft carried by a support, a driven element for each power device carried on said main shaft, said driven elements rotatable relative to said main shaft, individual means connecting a power device and a driven element, said individual means moved by each power device to rotate each driven element, a collar for each driven element fixed to said main shaft, an in dividual abutment carried by each collar, an individual finger carried by each driven element and extending into the path of movement of an abutment, means rotating said main shaft to move an abutment into engagement with a finger, each of said individual means rotating its driven element and finger in an arc in response to movement of its power device, the finger moved by the power device closest to said first position rotating the least and extending into the path of rotation of an abutment to prevent said main shaft from rotating, means connected to said main shaft to translate the angle of rotation of said main shaft into the position of said power device closest to said first position.

References Cited in the file of this patent UNITED STATES PATENTS 1,578,867 Taylor Mar. 30, 1926 1,578,882 Earle Mar. 30, 1926 1,685,749 Pfau Sept. 25, 1928 1,706,812 Pfau Mar. 26, 1929 1,914,679 White June 20, 1933 2,053,797 King Sept. 8, 1936 2,158,108 Deglon May 16, 1939 2,241,077 Thoma May 6, 1941 2,365,905 Rheingans Dec. 26, 1944 2,491,059 Ring Dec. 13', 1949 2,635,847 Rued Apr. 21, 1953 FOREIGN PATENTS 279,854 Germany Aug. 20, 1913 277,949 Italy Sept. 25, 1930 

